Stone library / Tourmaline / Tourmaline GroupTourmalineA practical tourmaline family guide: what this borosilicate mineral group is, how color varieties differ, what visual clues can and cannot prove, and how to wear and care for it.Traditional birthstone: October (alternative).Terminology: In Chinese jewelry contexts, tourmaline may be called bìxǐ. Black tourmaline is commonly known as schorl.Illustrative Tourmaline image. Appearance alone cannot confirm the exact material, treatment, origin, or value of a specific piece.What is tourmaline?Tourmaline is a complex borosilicate mineral group rather than one fixed chemical species. Its general formula is XY₃Z₆Si₆O₁₈(BO₃)₃W₄; the elements in those sites vary across the group. Tourmaline commonly has a Mohs hardness of 7–7.5, density of approximately 3.03–3.25 g/cm³, and refractive index around 1.62–1.64.What gives it its color?Varied: Mn²⁺ (pink/red), Fe³⁺/Cr³⁺ (green), Fe²⁺ (black), Cu²⁺ (Paraíba blue)Where does it come from?Major sources include Brazil, Madagascar, Nigeria, Mozambique, Afghanistan, USA.Treatments and how to spot themHeat and irradiation can modify color. Most tourmaline is untreated. Paraíba tourmaline is often heat-treated to enhance color.Important: Visual clues such as inclusions, color patterns, or surface features can provide preliminary observations, but they cannot replace refractive index, specific gravity, microscopic examination, and laboratory testing for a definitive identification. Treat visual clues as starting points, not final answers. Jewelry and care tipsWith hardness 7–7.5, tourmaline is suitable for rings, pendants, earrings, and bracelets. Clean with warm soapy water and a soft cloth. Avoid ultrasonic cleaners unless the stone is known to be fracture-free. Store separately from harder gemstones.Cultural beliefs and symbolismTourmaline carries cultural meaning across many traditions — these are folkloric and cultural traditions, not scientifically verified properties. Its associations vary by culture, and its use in astrology, chakra, or feng shui contexts should be understood as cultural expression rather than factual claims.What affects its value?Price is determined by color saturation, clarity, cut quality, and size. Before buying: ask the seller to confirm the material identity, treatment status, dimensions, and return policy in writing.Frequently asked questionsWhat is tourmaline?Tourmaline is a family of complex borosilicate minerals. Black tourmaline, rubellite, watermelon tourmaline, and Paraíba tourmaline are variety or market names that should be matched to the underlying identity and any treatment disclosure.How can I identify tourmaline?Color, zoning, inclusions, and crystal shape can provide preliminary clues, but they cannot confirm species or treatment on their own. For an expensive or disputed stone, use a qualified gemologist or independent laboratory report.Is tourmaline durable for jewelry?At about Mohs 7–7.5, tourmaline can suit many jewelry designs, but fractures, inclusions, thin edges, and setting exposure still matter. Ask about the individual stone rather than relying on the family name alone.Use this guide as a starting pointFor a costly or disputed stone, ask for species, treatment, and origin information in writing. An independent laboratory report is stronger evidence than a marketing phrase.Return to TourmalinePrevious guideTopazNext guideBlack TourmalineSources: GIA reference and the GemVerity editorial method. Last reviewed: 2026-08-22. This is an educational guide, not a gemological identification report. Cultural beliefs described above are folkloric traditions, not scientific guarantees.